Impact of cold block shapes on heat transfer and mixed convection in a ventilated square cavity with Ag/water nanofluid

Abstract

This study investigates mixed convection in a ventilated square cavity filled with an Ag/water nanofluid, containing central cold blocks of various shapes (square, circle, triangle, and ellipse). The goal is to understand the impact of nanoparticle concentration and the geometric shapes of the blocks on heat transfer. In the cavity, the inlet is located in the upper left corner, while the outlet is positioned in the lower right corner. Mixed convection is induced by cooling at the inlet of the ventilated cavity and uniform heating of its lower wall. The equations governing the flow of an incompressible Newtonian nanofluid are assumed to be two-dimensional, stable, and laminar. The finite volume method is used for numerical simulations. The effect of four different geometric shapes of the cold obstacle (circular, square, triangular, and elliptical) on fluid flow and heat transfer rate is also explored. The results show that increasing the nanoparticle concentration enhances heat transfer within the cavity. This improvement is particularly notable when the central cold obstacle takes on a circular shape, leading to better mixed convection and a higher heat transfer rate. The square and triangular shapes yield similar, albeit slightly lower, results, while the elliptical shape is the least effective for heat transfer.